Masticating, that is, an action including chewing and crushing food, mixing well the food with saliva, making a wet mass of food with a proper size, and preparing to be swallowed is necessary when a human eats a solid. Masticating also provides a waking effect and a relaxing effect; prevents obesity, dementia, a decrease in vision, distortion in posture, a cavity, a cancer, etc.; and provides an effect of restricting a change with age by an increase in volume of blood in the brain.
This masticatory ability (masticatory efficiency) is affected by many conditions, such as the number of teeth, whether teeth being healthy or not, occlusal form, periodental condition, jaw shape, masticatory muscle strength, mandibular motion pattern, age, and prosthesis condition.
A method of evaluating the masticatory ability may be, for example, a method in which a peanut or a raw rice is masticated by a human a predetermined number of times and the condition of the masticated peanut or rice is observed (screening method) or a method in which a color changeable chewing gum is masticated by a human a predetermined number of times and a change in color of the masticated gum is observed (color changeable gum method).
However, the screening method has low reproducibility, and the measurement time takes about 24 hours. Also, the observation result of the color changeable gum method cannot be quantified, and this method does not observe the masticatory ability, but actually observes the mixing ability.
Owing to this, the inventors and others of the present invention have developed an artificial food mass containing “microparticles that are in a substantially uniform spherical shape and have a property of being finely crushed and ground by masticating” and a system that evaluates the masticatory function by using this artificial food mass (PTL 1).
The system for evaluating the masticatory function includes a step of allowing a human to masticate an artificial food mass containing microparticles that are finely crushed and ground by masticating and have a spherical shape unless the microparticles are masticated; a step of enlarging the artificial food mass masticated by applying pressure to a proper thickness with which the microparticles are not pressed and crushed while sandwiching the masticated artificial food mass between two preparation sheets; and a step of counting the number of microparticles retaining the spherical shape that remain in the artificial food mass enlarged between the two preparation sheets by applying the pressure.
With this method, the number of “particles not finely crushed or ground” can be counted without using an organic solvent or expensive equipment for evaluation.